The standard for acquitting is reasonable doubt. You're presumed innocent until proven guilty, so in theory you aren't necessarily required to prove your innocence beyond a shadow of a doubt. While it may work differently in practice at times, that idea IS actually a great one.
So yes, it may still be possible that someone who is acquitted is in fact guilty, but the prosecution isn't allowed a second chance.
The standard for acquitting is reasonable doubt. You're presumed innocent until proven guilty, so in theory you aren't necessarily required to prove your innocence beyond a shadow of a doubt. While it may work differently in practice at times, that idea IS actually a great one.
So yes, it may still be possible that someone who is acquitted is in fact guilty, but the prosecution isn't allowed a second chance.